Find an item like [Night Reaver] at Wowhead and click the "Link" button (usually at the upper right.

Copy the line the popup window provides which will look like: /script DEFAULT_CHAT_FRAME:AddMessage("Shift-click this to place a link into a chat message: \124cff0070dd\124Hitem:1318:0:0:0:0:0:0:0:0\124h[Night Reaver]\124h\124r");

Switch back to World of Warcraft and paste the code into your chat window and press enter.

You should be able to shift-click the link that appears into other chat windows.